Small rodents such as mice, rats, guinea pigs, and hamsters are used in scientific research and they are sometimes kept as pets by children. Typically, such animals are held in small cages where they are provided with nesting material along with food and water. Solid food is kept in a feeding device. So that the cage remains dry and relatively orderly, liquids, such as water and medicines, are usually stored in a special bottle with a dispensing device that allows small portions to be released to the animal.
A common type of dispensing device, widely used in the laboratory animal industry, is a sipper tube that is connected to a bottle filled with liquid. The tube points downward and is accessible to the animal. Often the hole in the tube is relatively small and, therefore, surface tension, along with a partial vacuum that is created in the bottle, prevents liquid from flowing freely from the bottle. Other sipper tubes include ball bearings disposed therein to block the hole at the bottom of the tube. The bearing is free to move, and when it does, it allows liquid to exit in a controlled manner.
In the prior art, it is well known that a sipper tube—such as the one just described, can be coupled to a bottle with a stopper made of rubber, neoprene, or another similar material. The stopper is placed in the mouth of the bottle where it is held by friction fit. Similarly, a hole in the stopper is dimensioned to hold the sipper tube by friction fit. With the bottle inverted, the sipper tube is accessible to an animal, and limited amounts of liquid can flow out of the bottle as needed.
The use of a simple friction fit between the stopper and the bottle has at least one major limitation. Because the bottle is inverted, the weight of the liquid tends to loosen the stopper. Furthermore, the stopper is loosened by vibrations and motion caused by an animal using the bottle. These loosening effects may eventually cause the stopper to come apart from the bottle, allowing liquid to escape. In some cases, animals attempt and sometimes succeed in removing stoppers from the bottle. In order to avoid these potentialities, stoppers are usually inserted into the bottle by hand with relatively high force. However, this action may cause health problems, such as carpal tunnel syndrome, for a person who must repetitively insert stoppers into bottles. After all, typical laboratories utilize large quantities of these bottles and stoppers.
Thus, what is needed is an improved removable cap assembly that overcomes prior art limitations. Specifically, these limitations include the rigidity and security with which the sipper tube is held by a stopper in the bottle. Additionally, problems with regard to cleanliness stem from design features in the prior art.